US 20080164803 A1
A light bulb (1) is provided at the end thereof with an adapter (13) made from ceramic polymer, fixed in a multi-piece socket base (12).
1. An electric lamp, in particular a high-pressure discharge lamp, comprising a base mounted at one end and having an axis (A) and an inner vessel (2, 3) which is sealed in a vacuum-tight manner, said inner vessel being surrounded by an enveloping part (24), a base with electrical terminals bearing the inner vessel, on the one hand, and the enveloping part, on the other hand, characterized by the combination of the following features:
a) the base has a base insulator (12) which is produced from an insulating material and has a central opening (11) with a surrounding collar (13; 63), in which the inner vessel is accommodated by means of a cementless fastening means;
b) the base insulator has a fastening means for the enveloping part;
c) the enveloping part has, at the base end, an opening, a means for fastening it to the base insulator being located in the vicinity of the opening;
d) the enveloping part is fastened to the base insulator by means of a cementless mechanical holding mechanism incorporating the means from b) and c);
e) the cementless fastening means is an adapter part, which consists of a ceramic material, in particular of polymer-ceramic;
f) the base insulator and the adapter part have matching holding means, referred to below as indexing and mating indexing.
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14. A process for producing a lamp as claimed in
a) producing a basic lamp without a base insulator and enveloping part as known per se and providing a multi-part base insulator and an enveloping part having a pretreated edge region of its opening;
b) attaching an adapter part with indexing at one end of the basic lamp;
c) fixing the enveloping part and the modular unit comprising the adapter part and the basic lamp in relation to one another and attaching the parts of the base insulator;
d) connecting the parts of the base insulator and attaching base contacts.
The invention is based on a lamp, in particular a high-pressure discharge lamp or incandescent lamp, comprising a base mounted without cement, in accordance with the precharacterizing clause of claim 1. Of particular relevance here are metal-halide lamps, high-pressure sodium lamps or halogen incandescent lamps having a pinch seal at one end and a ceramic base part, but also conventional incandescent lamps.
EP-A 1 009 013 and the prior art cited therein have disclosed a lamp in which the base consists of a conventional ceramic material. Such a base needs to be connected to the bulb either by means of cement or by means of a separate element producing the connection, such as a metal spring, for example. In addition, the poor workability of the conventional ceramic materials results in complex fastening and insertion of electrical parts of the base. In particular, fastening of the contact elements and possible installation of a fuse can only be implemented very laboriously. In addition, in the case of the use of base cement, the amount of time taken is very considerable owing to the baking that is required.
DE-C1 43 17 252 has already disclosed a lamp comprising a base mounted without cement which comprises three bulbs. It has a ceramic adapter, which is fitted to a screw-type base. Atmospheric pressure prevails between the envelope and the outer bulb.
The object of the present invention is to provide a lamp in accordance with the precharacterizing clause of claim 1 which can be produced easily and quickly and nevertheless withstands high loads. A further object is to provide a lamp comprising a base mounted at one end in accordance with the precharacterizing clause of claim 1 which is simple to fit and can be produced in a manner which can easily be automated.
This object is achieved by the characterizing features of claim 1. Particularly advantageous configurations can be gleaned from the dependent claims.
The invention makes it possible in a simple manner to fix the inner vessel of a lamp held at one end by means of a holding apparatus, which is in the form of an adapter, whose holding function is realized without base cement. The lamp is therefore particularly suitable for simple mechanical and automated manufacture on production lines without hot processes such as fuse-sealing, welding or soldering, for example. In addition, long process times, for example for drying, baking or pumping, are avoided. The inner vessel is fixed without the use of cement by means of an adapter part consisting of ceramic, in particular of polymer-ceramic. The material as described in DE-A 195 12 407 or else DE 41 20 833, for example, is suitable as the polymer-ceramic.
The inner vessel rests with an end section, usually a pinch seal or else a fuse seal, in the adapter part, where it is held, for example, by means of an interlocking connection. However, in this case the inner vessel may perfectly well have a second end section in the sense of an axially arranged tubular lamp, as are often used in motor vehicle headlamps. The lamp is often a discharge lamp or a halogen incandescent lamp.
In principle, the lamp according to the invention has an enveloping part, in particular an overlapping bulb. This bulb is often manufactured from quartz glass or hard glass. The term enveloping part should be understood here expressly also in the broader sense, for example in the sense of a reflector dome of a reflector lamp. Often, the inner vessel, often referred to here as the basic lamp, is the only bulb of a discharge lamp or incandescent lamp, but this bulb may possibly be provided with an additional outer bulb. The enveloping part generally has one or two ends. However, this function is not relevant in the context according to the invention. It is merely of interest that one end acts as an anchor part for fastening the base. In addition, one or two power supply lines are passed to the outside through the enveloping part at this end. According to the invention, the adapter is manufactured from a material which withstands high temperatures, in particular from plastic or from ceramic, in particular polymer-ceramic.
The term polymer-ceramic means a ceramic consisting of a material which is also referred to as a polymer-ceramic composite material or polymer matrix composite material or polymer-ceramic composite.
In general, the power supply lines are passed out downwards at the adapter. The adapter surrounds, shaped in the form of a “U”, with two limbs a central part in the region of the broad sides of the pinch seal and also has a bottom part connecting the limb parts.
In principle, the adapter can be produced in advance as a component part. Particularly preferably, the inner vessel including the power supply lines protruding from it are manufactured in advance and only then is the adapter material applied to the power supply lines as an injection-molding compound, the compound being injection-molded around the power supply lines.
The material of the adapter is preferably a polymer-ceramic, in particular a composite material. In this case, the composite material may be inorganic, organic or a mixture of organic and inorganic components.
Such materials are known per se, for example from the literature such as the textbook Werkstoffe [Materials], Springerverlag, ISBN 3540573259. Known materials are, for example, carbide and nitride materials of inorganic polymers. The thermal stability of silicon carbonitride ceramics is very high.
The production of the lamp takes place in principle using the following process steps:
a) producing a basic lamp as known per se and providing a multi-part base insulator, for example comprising two or four similar parts, and an enveloping part having at least one opening at a neck part, which opening is equipped with a pretreated edge region; the pretreatment relates to the edge which is designed such that it maintains an outwardly protruding holder; the deformation is designed such that the outer diameter is greater than that of the neck region of the enveloping part;
The process for producing the lamp is based in particular on the current principles of processing polymer-derived ceramics. One decisive advantage is their potentially simple processing in terms of plastics technology so as to form complex molded parts by means of extruding or injection-molding polymeric compounds and by means of cold-processing polymeric molded parts. Subsequent thermolysis gives the ceramic component part. The volume shrinkage associated with the conversion of the polymer to the ceramic can be set in a targeted manner by adding active or inactive fillers. Special mention should be made of the excellent stability at high temperatures of amorphous Si(B)CN compositions. They are characterized by a high resistance to oxidation and a high creep resistance; crystallization takes place only above from 1400° C. to 1600° C. The polymer-ceramic transformation plays a decisive role in the abovementioned process for producing novel ceramic materials. Furthermore, the thermal stability of the carbonitrides produced is advantageous in terms of decomposition and corrosion. The manufacture can therefore be considerably simplified.
In a particularly preferred embodiment, the adapter is injection-molded directly to the inner vessel. In this case, the material of the adapter needs to be matched carefully to the material of the inner vessel, for example in terms of adhesiveness and the coefficient of thermal expansion. In this embodiment, an additional component part such as, for example, a spring element or base cement, is not required. The inner vessel and the adapter are automatically always centered with respect to one another owing to the production. The number of manufacturing steps is markedly reduced, and the heat dissipation during operation of the lamp is improved in comparison with a conventional ceramic. The automization is simplified in every respect.
On the one hand, thermoplastic injection-molding compound can generally be used in the production process. Typical examples of this class of materials are PEEK (polyether ether ketone), PPS (polyphenylene sulfide) or PPO (polyphenylene oxide). Polyamide can also be used. Another technique is the use of thermosetting transfer-molding compounds of organic or inorganic compositions. A typical example is Bakelite. In particular phenol resins or epoxy resins are used here. A specific material example is Cermosil 300 by HITK.
A further embodiment of the base insulator, which in particular comprises two half-shells, uses plastic. In contrast to a base insulator consisting of ceramic, in this case an additional snap-action connection is usually used which fixes a) the outer bulb and b) the basic lamp receptacle in the base insulator and therefore does not require any additional joining element such as an aluminum ring for the base insulator. A further possibility for joining the half-shells may also be an ultrasound connection between the plastic half-shells. At the same time, in this solution a metal spring for fixing the basic lamp in the adapter is not required, but instead it is now possible to connect the adapter, by means of an injection-molding process, directly and cohesively to the basic lamp itself. The basic lamp is also inserted into the injection mold itself, and the plastic or the ceramic is injected directly round the lamp.
A further possibility is to plug the basic lamp with a pinch seal with tight tolerances into a shaft with tight tolerances of the adapter without an intermediate element. For this purpose, however, greater value needs to be placed on the dimensional accuracy of the individual parts.
Preferred is the possibility of working with a so-called injection-molding ceramic, which withstands temperatures of up to 600° C., since 320° C. is still measured at the pinch seal of the lamp. In the case of low-wattage lamps, however, a PEEK may be sufficient. In particular, PEEK is very suitable as the material for the half-shells, but the plastic of the adapter should in this case withstand as high temperatures as possible.
Specifically, the present invention is concerned with an electric lamp, in particular a high-pressure discharge lamp, comprising a base mounted at one end and having an axis and an inner vessel which is sealed in a vacuum-tight manner, said inner vessel being surrounded by an enveloping part, a base with electrical terminals bearing the inner vessel, on the one hand, and the enveloping part, on the other hand.
The base has a base insulator which is produced from an insulating material and has a central opening with a surrounding collar, in which the inner vessel is accommodated by means of a cementless fastening means. The base insulator has a fastening means for the enveloping part. The enveloping part has, at the base end, an opening, a means for fastening it to the base insulator being located in the vicinity of the opening. The enveloping part is fastened to the base insulator by means of a cementless mechanical holding mechanism incorporating the abovementioned means. The cementless fastening means is an adapter part, which consists of polymer-ceramic.
Advantageously, the base insulator comprises at least two, preferably up to four, parts, which are in particular welded to one another by means of ultrasound. In this way, the base insulator can surround and hold the adapter in a simple manner.
In order to fasten the adapter in the base insulator, mechanical means are used. Preferably, the adapter part has a radially acting indexing, in particular a radially protruding projection, in the vicinity of its end which is remote from the inner vessel, which indexing interacts in holding fashion with at least one mating indexing interacting therewith, in particular a cutout of the collar in the interior of the central opening.
A particularly favorable feature of this basic design is the fact that it is possible to arrange a plurality of identical mating indexings, in particular cutouts, of the collar along the axis (A), with the result that the indexing, in particular the projection, can be inserted in the collar with differing physical depth.
Specifically, the indexing can be in the form of a groove, sickle, tooth, peripheral web or peripheral groove. Preferably, the indexing is attached to the bottom part of the adapter, but it may also be positioned slightly higher laterally on the limb parts. However, it should not be attached higher than 30% of the axial length from the end of the adapter, in order to ensure a secure fit of the inner vessel.
In general, the mating indexing needs to have the matching mating shape to the indexing, at least in outline. In this case, at least the contours fit together, for example a projection fits with a cutout.
In particular, the adapter is produced from one of the following materials: a composite material or a thermoplastic or thermosetting plastic. In this case, a composite material is to be understood in such a way that it is either inorganic, organic or a mixture.
Advantageously, the base insulator consists of a high-temperature plastic. A specific example is ULTRASON®, for example type 2010, by BASF, which is a PESU, i.e. a polysulfone or polyether sulfone.
The connection between the adapter and the inner vessel is alternatively such that the adapter is fastened in clamping fashion to the end of the inner vessel, in particular with spring clamps. An alternative is for the limb parts of the adapter to be pressed slightly inwards when the base insulator is joined, indirectly by means of force transfer means, for example tongues, which protrude radially, and therefore ultimately to bring about the clamping effect. However, this requires a material with a spring action for the adapter.
The present concept is suitable in particular for a modular lamp construction for outer bulb and reflector lamps. In addition, for operation in open and closed luminaires, it is suitable for simple, mechanical, automated manufacture on production lines without hot processes (fuse-sealing, welding, soldering) and without long process times (drying, baking, pumping).
A particular advantage is the fact that different light centers can be set by means of a suitable adapter system. Owing to the low manufacturing tolerance, for example in the case of an injection-molding production, the inner vessel can be inserted into the adapter in directly clamping fashion, i.e. without a spring part.
In order to make it possible to accommodate the adapter in the base insulator, which is preferably produced from high-temperature plastic, it should be manufactured in a plurality of parts, and at least in two parts. This circumstance also advantageously makes it possible to fasten (for example by means of clamping) an enveloping part on the base insulator in a simple manner. In this case, it may be favorable for a spring action to provide slits in the enveloping part. In the case of the use of high-temperature plastic parts for the base insulator, these parts can be welded by means of ultrasound welding.
A basic lamp body, often referred to as the inner vessel, which, owing to the modular design of the lamps, is often a mass-produced product, for example a ceramic discharge vessel for a metal-halide lamp with an outer bulb, is inserted, via the pinch seal or fuse seal of the outer bulb, into the ceramic lamp adapter, preferably consisting of polymer-ceramic, preferably produced in an injection-molding process.
The invention will be explained in more detail below with reference to a plurality of exemplary embodiments. In the drawings:
An exemplary embodiment of a metal-halide lamp 1 is shown in a side view in
The adapter 13 (see
The limb parts 14 are connected to one another at their bottom via a bottom part 16, with the result that the adapter is in this regard in principle in the form of a U. An exemplary embodiment of the adapter 13′ in accordance with this principle alone is shown in
In the exemplary embodiment in
The base insulator 12 (
The particular feature of the base insulator in the preferred embodiment shown is the fact that it has a plurality of channels 18 arranged axially one above the other. In total four channels 18 are shown in
The adapter 13 is fitted into the base insulator 12 (as shown in
By selecting the opening width of the insertion shaft 15 of the adapter and the design of the limb parts 14 to be suitably narrow, the basic lamp is alternatively clamped directly by means of the pinch seal 9, which prevents the basic lamp from sliding out owing to the tight tolerance. In this case, a spring element is no longer required.
Alternatively, the base insulator may have inwardly protruding buttons 56 on its upper edge of the opening, which buttons press the upper free end of the collar part 14 inwards and therefore fix the pinch seal of the basic lamp in clamping fashion. In this case, the adapter 13 itself needs to consist of plastic and needs to permit a certain spring action of the limb parts 14.
The base insulator 12 may be designed to have a plurality of parts, preferably two parts and at most four parts. The design of the base insulator with a plurality of parts also permits simple accommodation of an enveloping part, see
A two-part adapter, preferably consisting of polymer-ceramic, is in principle also possible.
A separately manufactured adapter has the advantage that, owing to suitable dimensions of the lamp adapter, different light centers can be set without needing to change the base insulator. Given a design of the base insulator with a plurality of parts, the lamp adapter and the enveloping part are inserted into one half of the base insulator. The second half of the base insulator is then joined and connected to the first half by means of a suitable connection technique, for example ultrasound welding.
If different light centers are desired, the lamp adapter is given an indexing, preferably a bead, or button or a groove, sickle, tooth or the like or a peripheral web or a peripheral groove at a certain height. In this case, the base insulator is provided with a plurality of mating indexings required for different light centers, for example rows of grooves, sickles or webs. Owing to a corresponding insertion height during fitting, the desired light center is thus set.
In a preferred embodiment, the opening edge of the enveloping part is designed such that it is prevented from being twisted or withdrawn. The protection against twisting is ensured, for example, by one or more sickles, grooves or the like being introduced on the enveloping part which interact with bulges 21 on the base insulator 12′, see
The enveloping part 23 is prevented from falling out of or being withdrawn from the base insulator 12 by a shoe-shaped enlarged portion 24 at the opening edge of the enveloping part, for example the enlarged portion is provided at the opening by means of the edge region 25 of the enveloping part being beveled in the vicinity of the opening towards the outside (up to 90°) or by means of flame-rounding, which can form a bud 26 on the edge region 25 of the enveloping part, see
The base insulator 12 advantageously has a peripheral channel 30 on its surface which points towards the enveloping part 23, which channel 30 runs in the vicinity of the outer edge (
The electrical contact (
When correspondingly shaping the injection-molded high-temperature plastic or polymer-ceramic parts, given a multi-part design of the base insulator 12, metallic contact parts, for example insulation displacement or clamping connections, can be inserted into the opening 51 of the base insulator or into the opening 15 of the lamp adapter 13 before it is closed and welded.
These clamping connections are then prefabricated with correspondingly long power supply line extensions. The base contact 20 is fixed mechanically on the base insulator 12 by means of deformation, for example crimping, as is known per se, or the adapter receptacle itself forms the base.
Protection against electric shock for the base system is ensured in an ideal extremely simple manner by the adapter 13′ surrounding the pinch seal of the outer bulb by being injection-molded around it (
For production purposes, in particular a modular unit comprising the basic lamp which is finished per se is provided whose power supply lines 3 are particularly long in comparison with the conventional technology or are already connected to the contact pins 4. This takes place, for example, by means of crimping or welding. For the connection to the adapter, the basic lamp is provided with a provisional holder. This then acts as an adjustment aid and stop for the injection-molding die into which the precursor material of the adapter is introduced.